I haven't come across this before and can't imagine what it would be like for someone that is unable to drink water - especially as we are made up of about 70% water and every cell in our body needs it in order to cleanse, nourish and energize!
What I would say though is that it may have something to do with the type of water the person is drinking (tap water is acidic and full of toxins and most bottled mineral water isn't alkaline enough). I would imagine someone who can't tolerate this water is also allergic to many other things too.
A great pioneer in natural health, Adele Davis, believed allergies to be a result of stress. My daugher, who suffered for many years from all kinds of allergies, eczema and asthama, is a highly strung girl and gets upset easily. So I very much believe this. But through giving her a combination of natural remedies - including alkalizing water, a blend of omega oils, apple cider vinegar, raw honey, etc she is now cured!
Back to water tho - I believe that if you are allergic to water you can cure yourself through these remedies - including being able to drink alkalizing water (a pH above 7.5) - as an acidic body is also an allergic body and this will help to bring it back to an alkaline state by flusing out the toxins and acids that are making it allergic.